The present invention relates to the use of hyaluronidase in the manufacturing of a pharmaceutical for the treatment of a mammal suffering from inflammation associated with an increased local synthesis of hyaluronan. More specifically it relates to the use of hyaluronidase in the manufacturing of a pharmaceutical for the prevention of inflammatory cell infiltration caused by hyaluronan.
Hyaluronidase is an enzyme produced in e.g. mammals, leeches, and krill and which is extractable from a number of tissues. Hyaluronidase degrades a mucopolysaccharide called hyaluronan, also referred to as hyaluronic acid (Balazs E A et al, Biochem J 1986; 235: 903). Hyaluronan is an important stabilizing constituent of the loose connective tissue and is produced by the mesenchymal cells (Comper W D, Laurent T C, Physiol Rev 1978; 58: 255-315).
The content of hyaluronan in an organ has been shown to increase in different conditions of inflammation of that organ. Thus, an increased concentration of hyaluronan has been shown in tissue from different organs characterized by a condition of inflammatory-immunological injury such as alveolitis (Nettelbladt O et al, Am Rev Resp Dis 1989; 139: 759-762) and myocardial infarction (Waldenstrxc3x6m et al, J Clin Invest 1991; 88(5): 1622-1628). Other examples of this type of conditions are the allograft rejection after a renal (Hxc3xa4llgren et al, J Exp Med 1990a; 171: 2063-2076; Wells et al, Transplantation 1990; 50: 240-243), small bowel (Wallander et al, Transplant Int 1993; 6: 133-137) or cardiac (Hxc3xa4llgren et al, J Clin Invest 1990b;85:668-673) transplantation; or a myocardial inflammation of viral origin (Waldenstrxc3x6m et al, Eur J Clin Invest 1993; 23: 277-282).
Hyaluronan is a compound with a pronounced water binding capacity (Mason R M, Progr Clin Biol 1981; Res 54:87-112). An enhanced local production and accumulation of hyaluronan in the connective tissue of an organ therefore leads to a local accumulation of liquid, with a risk of harmful interstitial tissue edema, which in turn may lead to an impairment of the function of that organ.
It is clear that this accumulation of hyaluronan in e.g. an organ in a state of inflammation may bring about very severe consequences. In the case of an organ transplantation it also may lead to irreversibility of a rejection of the organ and in some cases eventually to a life threatening condition. Therefore it exists a great demand for a method of alleviating this state of risk. The object of the present invention is to provide a means of achieving this.
Hyaluronidase has previously, in the seventies, been used to reduce the effects of myocardial infarction (Maroko P R et al, Circulation 1972; 46(3): 430-7; Maclean D, et al, Science 1976; 194(4261): 199-200). The mode of action was however not understood. In an in vitro animal model cardiac performance after ischemic injury was improved upon administration of hyaluronidase (Rovetto M J, Circ-Res 1977; 41(3): 373-9; Fischer J H et al, Transplantation 1994; 58(6): 748-53).
In spite of the fact that for a certain time already it has been known that interstitial edema by a graft rejection could be the result of an interstitial accumulation of hyaluronan, it never has been proposed to make use of hyaluronidase to overcome the very serious clinical problem of allograft rejection due to inflammation.
In fact there existed several reasons for the persons skilled in the art not to believe this would be an operable solution to the problem.
Firstly, it was regarded as most improbable that the enzyme would reach the inflamed tissue.
Secondly, even if the enzyme did reach the inflamed tissue, it was regarded as improbable that it would be functional, since the pH optima of hyaluronidases are quite acidic, whereas the pH in the tissue is neutral.
Finally, it was considered that if the enzyme nonetheless would be active, then this might lead to a degradation of hyaluronan in the whole of the body, and not essentially only in the inflamed tissue.
Thus, although hyaluronidase has been used in laboratory tests on cell cultures and laboratory animals, there has been a general prejudice among the persons skilled in the art against its use on human beings.
Most scientists at present believe the inflammatory cells are recruited to the organs by means of them being on a specific mission to the organ. To our great surprise not only graft edema was diminished by hyaluronidase treatment but also inflammatory cell infiltration was reduced. This means that hyaluronan acts as a magnet for recruitment of inflammatory cells. This may be explained by the fact that lymphocytes carry receptors for hyaluronan. The function of these receptors were previously not understood.
The present inventors have been able to show that prophylactic treatment with hyaluronidase delays rejection of a non-immunosuppressed allograft and reduces inflammatory cell infiltrates. This finding means quite unexpectedly that hyaluronan acts as a magnet for inflammatory cells. This mechanism could be universally applied to reduce ongoing inflammation by means of reducing inflammatory recruitment. This to a man skilled in the art very surprising finding led the present inventors to develop a pharmaceutical based on hyaluronidase for the treatment of conditions of inflammation associated with an increased local syntesis of hyaluronan.
The object of the present invention consequently is the use of hyaluronidase in the manufacturing of a pharmaceutical for the treatment of conditions of inflammation associated with an increased local syntesis of hyaluronan.
Another object of the invention is to provide a method of treating conditions of inflammation associated with an increased local synthesis of hyaluronan, by systemic or local treatment with a pharmaceutical comprising hyaluronidase.
The invention will be described in further detail herein below and is defined in the appended claims.